The high energy density of thermal energy storage systems favors their use in vehicle propulsive systems. Unfortunately, the state of the art thermal vehicles have the inconvenience of low energy conversion efficiency. The state of the art electric vehicles that depend entirely on battery-stored energy for range have their design specifications limited by the requirements imposed by battery arrays that are heavy, bulky and expensive. These inconveniences have been cited in several documents, of which an example is a technical paper entitled “The Thermal Vehicle—A Pollution Free Concept” by Jack R. Kettler presented at the “Tenth Intersociety Energy Conversion Engineering Conference” held on Aug. 18-22, 1975.